How would I save my objects as-is in the middle of a rigid body simulation
The option you are looking for is 'Apply transformation' button under the physics tab in the toolbar of 3D view.



Select all the broken wall pieces and 'Apply transformation', when you are on the desired frame. After that, while all the pieces are still selected, click on that remove button. This removes the physics on these objects.You can join all these pieces with 'Ctrl + J', if you want to make them into one object.